The government’s top legal adviser says he will ignore a “radical” directive from Attorney-General George Brandis that prevents him giving advice directly to ministers and government departments, in the latest front in an escalating war between the country’s two most senior lawyers.

At a fiery Senate inquiry on Friday, Solicitor-General Justin Gleeson, SC, said a direction issued by Senator Brandis requiring ministers to obtain his written permission before seeking advice from Mr Gleeson was “unlawful”.

He said if the Governor-General or Prime Minister came to him directly for advice he would consider it his legal duty to make a “conscientious decision” to flout the direction and provide them with advice.

“It is a radical change,” Mr Gleeson said of the direction issued by Senator Brandis in May.

“Do I lie awake at night worrying about it? I have every night since 5 May, trying to determine how this could have come about and what is the correct way to try and respond to and remedy this situation.”

Legal experts have expressed concern the direction could see Mr Gleeson, who holds a statutory office and gives independent advice, “frozen out” from advising the government.

Mr Gleeson revealed on Friday that Prime Minister Malcolm Turnbull had sought his advice in confidence in January “on a matter which I won’t mention”. Senator Brandis was not privy to the request.

He said that, “read literally”, the new direction would prevent him providing that advice “and yet I consider it’s my duty to do that under the Law Officers Act”.

Appearing after Mr Gleeson, Senator Brandis said the direction was nothing more than “administrative housekeeping” and was consistent with the law and historical practice. He stood by “every word of every statement” he had made.

He said it was an “insult” to suggest, as former Commonwealth solicitor-general Gavan Griffith, QC, has claimed, that the direction was akin to keeping “a dog on a lead” because all barristers had an obligation to give frank and fearless advice.

He said the dispute with Mr Gleeson boiled down to a difference of opinion about the meaning of the word “consultation”. His understanding of the word was consistent with the Oxford English Dictionary definition but Mr Gleeson took a “narrower” view.

Senator Brandis conceded he did not raise the prospect of a binding legal direction with Mr Gleeson at a meeting on November 30 last year, saying he had not yet decided on that course of action.

However, he said his legal obligation to consult did not require it to be done “in some specific fashion” and there was consultation on the general “subject matter”.

Senator Brandis took aim at Mr Gleeson for having a conversation with shadow attorney-general Mark Dreyfus in June in which he denied he was consulted about the direction and said he did not agree with it.

He said Mr Gleeson “ought to have” told him about the conversation with one of the government’s “principal political enemies” during the election campaign and he was “shocked” he did not.

But Mr Gleeson said he considered it his duty to answer Mr Dreyfus’ questions and he was “also the shadow attorney-general, with responsibilities for these matters in the caretaker period”.

Mr Dreyfus said on Friday Senator Brandis had not put forward “the slightest justification” for the new direction.

“He was putting himself between the Governor-General and the Solicitor-General, he was putting himself between the Prime Minister and the Solicitor-General, he was putting himself between every secretary of a Commonwealth Department, every head of a Commonwealth agency,” he said.

Mr Dreyfus repeated his call for Senator Brandis to resign over the affair.

JOHN Howard was labelled a “racist” by dozens of protesters outside the University of Sydney’s Great Hall today, as former prime minister John Howard addressed an audience after receiving an honorary doctorate.

Mr Howard was awarded the doctorate in recognition of the gun legislation he passed in the wake of the Port Arthur massacre.

However, about 50 protesters managed to delay the ceremony for 15 minutes while they accused Mr Howard of war crimes for his decision to follow the US into the Iraq war.

One man was even arrested for “breaching the peace” and taken to Newtown police station.

He was later released without charge.

Mr Howard graduated from the university in 1961 and has credited it with much of his success.

The 77-year-old ignored the protesters and spoke about the pressure of making the right decision in the moment.

“I often reflected upon the things that we got right, as well as acknowledging from time to time the things we hadn’t got right,” Mr Howard said.

“Being an intense Australian nationalist, I always thought the balance of the things we got right was quite decisive.”

Meanwhile, independent MP Andrew Wilkie criticised the University of Sydney, describing its decision to honour Mr Howard with the doctorate as “preposterous”.

“This is the man that took us to war on a lie, and helped create the current anarchy in the Middle East and the terrorist threat we all live with today,” Mr Wilkie said.

He said Mr Howard, along with his US and English counterparts George W. Bush and Tony Blair, had the “blood of countless people on their hands” and should go before an international court for war crimes.

More than 100 academics from the University of Sydney signed a petition opposing the honour to Mr Howard, Mr Wilkie said.